Since the past, there have been monitoring cameras with two types of modes, that is, a day mode in which imaging is performed under daytime natural light or under illumination of visible light such as white light and a night mode in which imaging is performed by radiating infrared light.
In imaging in the day mode, it is possible to obtain color images. On the other hand, in imaging in the night mode, since reflected light of radiated infrared light reflected by a subject is received, color information such as R, and B is unable to be obtained, and only received light intensity of the reflected light (infrared light) is able to be acquired. Therefore, the obtained image is a monochrome image such as a gray image or a green image.
Meanwhile, considering the intended purpose of the monitoring camera, it is desirable to obtain a color image even in the imaging in the night mode.
In this regard, in the past, for example, a technique of consecutively capturing an image obtained in a state in which an imaging range (subject) is irradiated with infrared light (hereinafter referred to as an “infrared image”) and an image obtained in a state in which an imaging range is not irradiated with infrared light (hereinafter referred to as a “visible image”) and generating a color image using luminance information of the infrared image and chrominance information of the visible image has been disclosed (for example, see Non-Patent Literature 1).